About Plek Services
High-quality fretwork has always been a cornerstone of what we do here at Five Star Guitars. Whether it’s refretting a vintage instrument, or correcting minor defects or inconsistencies on brand new instruments, we’ve spent years developing our processes and skills needed to make your guitar play its best.
In our continued effort to provide the highest quality fretwork possible, we’re proud to be the first shop to bring Plek-technology to the state of Oregon. This state-of-the-art tool helps us achieve unparalleled levels of accuracy and consistency, and it’s become an integral part of our process when performing precision fretwork in the shop.
What Is Plek?
A Plek machine is a vertical 3-axis CNC mill that performs a wide variety of operations on the playing surface of a guitar with a high degree of precision—accurate to within ±.0002" tollerance. These operations include (but aren’t limited to):
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Fret Dressing
Our Plek machine allows us to level and crown frets to a high degree of accuracy, accounting for string tension, tuning, and action preference, and providing the most consistent, buzz-free setup possible. The 3-shape fret cutter cuts and crowns the frets to an accuracy of 1/100th of a millimeter
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Refrets
In addition to leveling frets, we use our Plek machine to level and prep fingerboards for fret installation during refrets. This grants us a greater level of control over fingerboard radius and fallaway, ensuring optimal conditions for fret installation.
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Diagnostics
A quick Plek scan can help us diagnose humps, twists, and other inconsistencies in customer instruments that might need to be addressed. It’s also a powerful tool we use to verify that the new and used guitars we stock meet our standards, or when working with a manufacturer to resolve quality control issues.
- Nut and Saddle Shaping
- Nut and Saddle Pocket Cutting
- Fret Slotting
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Inlay Channel Cutting
How Plek Works
When you’re doing fretwork by hand, the first step is usually to remove the strings, adjust the truss rod to get the neck as straight as possible, and then level the frets using a sanding beam. Once they’re level, you re-crown, polish, and string it back up, then adjust relief and action as needed. That method works, and we’ve used it for years—but it has a limitation: it only accounts for how the neck behaves without string tension. Leveling under simulated tension in an Erlewine Jig can get you closer, but still, a neck will behave differently when it's being pulled by the string tension, vs pushed into position by the Erlewine Jig.
A guitar has around 150 pounds of string tension pulling on the neck when tuned to pitch. That tension can introduce subtle warping or humps that don’t show up when the strings are off and the neck is straightened with the rod. Traditional leveling can’t fully account for those shifts—so you end up leveling to one shape, and playing under another.
With the Plek, we take a completely different approach. The machine starts by scanning the neck with the strings on and tuned to pitch, which gives us a detailed 3D map of the fingerboard and frets as they exist under real playing conditions. We can see relief, fret height variation, fallaway, high spots—everything.
Once the scan is complete and the fret plane is programmed, we remove the strings. The neck will naturally settle into back-bow, but the Plek remembers exactly how much material to remove from each fret to create a level surface under tension. That means the machine is actually cutting an intentionally uneven surface—one that becomes perfectly level when the strings go back on. The result is fretwork that’s dialed in more tightly than anything we could do by hand. After processing, the Plek performs a final scan with the strings back on, to verify the results.
This process is a lot more automated than the old fashioned way, but there’s still a human element; a skilled luthier is needed to determine if there are any other issues that need to be addressed before scanning and processing the instrument, such as a poorly set neck, or loose/improperly seated frets. Our luthier will also interpret the Plek scan, and program the ideal fingerboard/fretboard plane to achieve optimal playing conditions for your specific preferences. After processing, the luthier hand polishes the frets to a high gloss, before proceeding to restring and set up the instrument to your desired specs.
Why Use Plek on a Brand New Guitar?
All new and used guitars get a full setup before they hit our sales floor. We also carefully inspect every instrument for issues that might affect playability or long-term stability. If something doesn’t meet our expectations, we’ll send it back. On average, we return about 10% of the new instruments we receive.
Because of that level of scrutiny, the guitars we carry are usually capable of playing better than the same model bought elsewhere. However, in our experience, most factory produced guitars will still have minor inconsistencies in the playing surface, from high or improperly seated frets, to slight twists or humps in the fingerboard. For the discerning player, someone with specific setup preferences or a keen sensitivity to feel, a Plek fret dress can address these inconsistencies, and take their instruments setup to the next level.
A fret dress done on the Plek allows us to identify and address these minor inconsistencies that are impossible to detect by hand. We can also plane custom relief or fallaway profiles that are optimized for your specific action, tuning, or string gauge preferences, allowing for levels of accuracy and consistency that you’ll never get from an out-of-the-box factory produced guitar.
After Processing
Before Processing
Magnification Beyond the limits of human vision
Virtual Fret Dress
Slide to see the comparison before and after processing